An important and continuing goal in the data storage industry is that of increasing the density of data stored on a medium. For tape storage systems, that goal has lead to decreasing the track pitch and the track width in magnetic tapes, increasing the track density in recording tape heads, and the development of metal particle (MP) tape to replace conventional chrome tape.
MP tape, however, has a higher magnetic coercivity (on the order of three times greater) than conventional chrome tape. As a result, higher magnetic flux levels must be generated in recording heads in order to write data to MP tape. Conventional write heads in tape storage systems have magnetic poles constructed from ferrite based materials or the like. Such materials, however, have relatively low saturation magnetization levels, and therefore will not support the magnetic field required to write data to MP tape.
To solve this problem, some recording head manufacturers have used metal-in-gap (MIG) magnetic pole designs, as well as thin film heads having nickel-iron magnetic pole materials such as permalloy or the like. However, because of their lower resistivity, such materials are not well suited to higher frequency applications.
As a result, alternative magnetic pole materials, such as cobalt-zirconium-tantalum (CoZrTa) alloys, cobalt-zirconium-niobium (CZN) alloys, iron-nitride (FeN), or iron-nitride alloys, have been developed for use in high density tape storage systems. Such materials provide the high saturation magnetization levels (on the order of four times greater than conventional pole materials), high resistivity, low coercivity, and other magnetic properties required to write data to MP tape, and are suited for high frequency applications. The high saturation magnetization levels of such materials also permit the poles of the write head to be thinner, on the order of four microns.
However, the use of such new magnetic pole materials in high density tape storage systems has created problems in the conventional thin film manufacturing methods for recording heads, such as photolithography. More specifically, conventional processes creates a topography on which it is difficult to accurately deposit and process CoZrTa to create a coil center tap. Moreover, CoZrTa demonstrates different process characteristics depending upon the material of the underlying layer.
While these problems may be partially addressed by the use of ion milling processes or combined ion milling and photolithographic processes to fabricate a thin film write head, ion milling is an expensive process which increases the cost of the resulting recording element. Thus, there exists a need for a method for photolithographic fabrication of a thin film write head that overcomes the problems associated with the use of magnetic pole materials such as CoZrTa or the like.